ssf autocorrecting formats

README.md

@@ -5,6 +5,7 @@ Various spreadsheet file format notes.
 - [Data Interchange Format (DIF)](/dif/README.md)
 - [Symbolic Link (SLK/SYLK)](/sylk/README.md)
 - [XLSB Short Records](/xlsb_short_records/README.md)
+- [Number Formats](/ssf/README.md)
 
 Project sponsored by [SheetJS](https://sheetjs.com)
 

ssf/README.md

@@ -0,0 +1,18 @@
+# Number Formatting
+
+ECMA-376 includes general guidelines for number formatting specifiers.  `MS-XLS`
+has a sketch ABNF grammar
+
+
+### Auto-Correcting Number Formats
+
+Google Sheets and other third party writers employ number formats that are do
+not follow the formal grammar.  Excel will transparently auto-correct them when
+round-tripping.  Some of the known autocorrections are listed below:
+
+| Format | Correction |
+|:-------|:-----------|
+| `d.m`  | `d\.m`     |
+
+
+[![Analytics](https://ga-beacon.appspot.com/UA-36810333-1/SheetJS/notes?pixel)](https://github.com/SheetJS/notes)